7-pyrazolyl tetracycline compounds and methods of use thereof

ABSTRACT

The present invention provides compounds of Formula (I) and related methods and formulations: 
                         
wherein:
 
     A represents a pyrazole ring optionally substituted by one or more R groups.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/625,317, filed Nov. 24, 2009; which is a divisional of U.S. patentapplication Ser. No. 11/292,552, filed Dec. 2, 2005; which is acontinuation of U.S. patent application Ser. No. 10/858,616, filed Jun.1, 2004; which is a continuation of U.S. patent application Ser. No.10/636,436, filed Aug. 6, 2003; which is a continuation of U.S. patentapplication Ser. No. 10/295,417, filed Nov. 15, 2002; which is acontinuation of U.S. patent application Ser. No. 10/097,135, filed Mar.12, 2002; which claims the benefit of European Patent Application SerialNo. 01500064.9, filed on Mar. 13, 2001. The entire contents of eachaforementioned application are hereby incorporated herein by referencein their entirety.

FIELD OF THE INVENTION

The present invention relates to a novel class of chemical compounds andto their use in medicine. In particular, the invention concerns noveltetracycline derivatives, methods for their preparation, pharmaceuticalcompositions containing them and their use as antibiotic agents.

BACKGROUND OF THE INVENTION

Tetracycline derivatives are known for treating bacterial infections.However, there remains a need for tetracycline derivatives for thetreatment of Gram-positive, Gram-negative and community acquiredinfections. Moreover, there remains a need for tetracycline derivativeseffective against tetracycline resistant strains.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides compounds of Formula (I):

wherein:

-   A represents an aromatic 5 membered heterocycle, optionally    containing, in addition to the nitrogen atom indicated in Formula    (I), one to three additional nitrogen atoms and optionally    substituted by one or more groups “R” selected from    -   halogen,    -   —NRaRb,    -   C₁₋₆ alkyl,    -   C₂₋₆ alkenyl,    -   C₃₋₆ alkynyl,    -   aryl,    -   heteroaryl,    -   hydroxy,    -   —OC₁₋₆ alkyl,    -   formyl,    -   cyano,    -   trifluoromethyl,    -   —CHNORa,    -   —CO₂Ra,    -   —CONRaRb,    -   —NRaC(O)Ra,    -   —NRaC(O)ORa,    -   —OC(O)NRaRb,    -   —OC(O)Ra,    -   —OC(O)ORa,    -   or a C₁₋₆alkyl group substituted by one or more groups selected        from        -   hydroxy,        -   —NRaRb,        -   —OC₁₋₆alkyl,        -   —SRa,        -   —CHNOR,        -   —CO₂Ra,        -   —CONRaRb,        -   —NRaC(O)Ra,        -   —NRaC(O)ORa,        -   —OC(O)NRaRb,        -   —OC(O)Ra,        -   —OC(O)ORa-   Ra and Rb independently represent hydrogen or C₁₋₆alkyl (preferably    methyl);-   R¹ represents hydrogen, C₁₋₆alkyl or together R¹ and R³ represent a    CH₂ moiety;-   R² represents hydrogen, —OC₁₋₆alkyl, —O(O)C₁₋₆alkyl or hydroxy;-   R³ represents hydrogen, hydroxy or together R³ and R¹ represent a    CH₂ moiety;-   and pharmaceutically acceptable derivatives and solvates thereof.

Compounds of Formula (I) contain at least one asymmetric centre, denotedby *, and thus may exist as enantiomers or diastereoisomers. It is to beunderstood that the invention includes each such isomer, either insubstantially pure form or admixed in any proportion with one or moreother isomers of the compounds of Formula (I). The preferredstereochemistry at the centre where R¹ and R³ are substituents is whenR¹ is H, R³ is in the alpha-configuration (downwards). The preferredstereochemistry at the centre where R² is a substituent is alpha(downwards). The preferred stereochemistry at the centre where N(Me)₂ isa substituent in the ring is alpha (downwards).

The term “pharmaceutically acceptable derivative” as used herein refersto any pharmaceutically acceptable salt, or metabolically labilederivative of a compound of Formula (I), for example a derivative of anamine group, which, upon administration to the recipient, is capable ofproviding (directly or indirectly) a compound of Formula (I). It will beappreciated by those skilled in the art that the compounds of Formula(I) may be modified to provide pharmaceutically acceptable derivativesthereof at any of the functional groups in the compounds of Formula (I).Such derivatives are clear to those skilled in the art, without undueexperimentation, and with reference to the teaching of Burger'sMedicinal Chemistry And Drug Discovery, 5th Edition, Vol 1: PrinciplesAnd Practice, which is incorporated herein by reference. For examplecompounds of Formula (I) may be N-alkylated in the presence offormaldehyde and an amine such as methylamine to give the correspondingMannich base adducts.

Salts and solvates of compounds of Formula (I) which are suitable foruse in medicine are those wherein the counterion or associated solventis pharmaceutically acceptable. However, salts and solvates havingnon-pharmaceutically acceptable counterions or associated solvents arewithin the scope of the present invention, for example, for use asintermediates in the preparation of other compounds of Formula (I) andtheir pharmaceutically acceptable derivatives, and solvates.

Suitable salts according to the invention include those formed with bothorganic and inorganic acids or bases. Pharmaceutically acceptable acidaddition salts include those formed from trifluoroacetic, hydrochloric,hydrobromic, hydroiodoic, sulphuric, citric, tartaric, phosphoric,lactic, pyruvic, acetic, succinic, oxalic, fumaric, maleic, oxaloacetic,methanesulphonic, ethanesulphonic, p-toluenesulphonic, benzenesulphonic,and isethionic acids. Pharmaceutically acceptable base salts includeammonium salts, alkali metal salts such as those of sodium andpotassium, alkaline earth metal salts such as those of calcium andmagnesium and salts with organic bases such as dicyclohexyl amine andN-methyl-D-glucamine.

Suitable solvates according to the invention include hydrates.

The term alkyl, as used herein to define a group or a part of a group,unless otherwise stated, refers to a saturated straight or branchedalkyl chain containing from 1 to 6 carbon atoms. Examples of such groupsinclude without limitation methyl, ethyl, n-propyl, isopropyl, n-butyl,iso-butyl, sec-butyl, tert-butyl, neopentyl and hexyl.

The term “alkenyl”, as used herein to define a group or a part of agroup, unless otherwise stated, refers to a straight or branched alkenylchain containing from 2 to 6 carbon. Examples of such groups includewithout limitation 1-ethenyl, 1-propenyl, allyl(2-propenyl), 1-butenyl,2-butenyl, 2-pentenyl.

The term “alkynyl”, as used herein to define a group or a part of agroup, unless otherwise stated, refers to a straight or branched alkynylchain containing from 3 to 6 carbon. Examples of such groups includewithout limitation propynyl, butynyl or pentynyl.

The term “cycloalkyl” as used herein to define a group or a part of agroup, unless otherwise stated, refers to a saturated alkyl ringcontaining from 3 to 6 carbon atoms. Examples of such groups includecyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

The term “halogen” refers to a fluorine, chlorine, bromine or iodineatom. Suitably the halogen atom is selected from chlorine, bromine oriodine, preferably chlorine or bromine. Chlorine is most preferred.

The term “aryl group” refers to an aromatic mono or bicyclic ring systemcomprising from 5 to 10 carbon atoms and heteroaryl group is wherein oneor more of the carbon atoms is/are replaced by heteroatoms independentlyselected from nitrogen, oxygen and sulfur,

Suitably A represents pyrrole, pyrazole, 1,2,3-triazole, 1,2,4-triazoleand tetrazole.

Preferred substituents on A include ethoxycarbonyl, carboxaldehyde,cyano, dimethylaminomethyl, oxime and methyloxime.

Suitably, R² is selected from hydrogen, methoxy and hydroxy. Moresuitably, R² is selected from hydrogen and hydroxy. Conveniently, R² ishydroxy. Preferably, R² is hydrogen.

Suitably, R³ represents hydrogen or methyl. Conveniently R³ is methyl.Preferably R³ is hydrogen

Suitably the compound of Formula (I) is derivatised from a naturaltetracycline like compound. Examples of natural tetracycline likecompounds include tetracycline, chlortetracycline, oxytetracycline,demeclocycline, methacycline, sancycline, doxycycline, and minocycline.Preferably the natural tetracycline like compound is selected fromsancycline and doxycycline, most preferably sancycline.

It is to be understood that the present invention covers allcombinations of suitable, convenient and preferred groups describedhereinabove.

References herein after to compounds of the invention include compoundsof Formula (I) and their pharmaceutically acceptable derivatives andsolvates.

Examples of compounds of Formula (I) include:

-   [4(R,S)-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-(1H-Tetrazol-1-yl)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4-S-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-[(4-ethoxycarbonyl)-1H-triazol-1-yl]-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4-S-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-[(5-ethoxycarbonyl)-1H-triazol-1-yl    1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4S-(4aα,5aαα,12aα)]-4-(Dimethylamino)-7-(1H-pyrrol-1-yl-3-carboxaldehyde)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4S-(4aα,5aαα,    12aα)]-4-(Dimethylamino)-7-(3-((hydroxymino)-methyl)-1H-pyrrol-1-yl)-1,4,4a,5,5a,6,11,12a-octahydro-3,    10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4S-(4aα,5aαα,12aα)]-7-(3-Cyanopyrrol-1-yl)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,    10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide-   [4S-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-(3-((methyloxymino)methyl)-1H-pyrrol-1-yl)-1,4,4    a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

As demonstrated in the assays described below the compounds of thepresent invention show activity against the most important pathogens,including gram positive bacteria such as S. pneumoniae and S. aureus,and gram negative organisms such as H. influenzae, M. catarrhalis and E.coli. In addition, these compounds are active against gram positive andgram negative tetracycline resistant bacterial strains, including thosewith resistance mediated by efflux pumps and ribosome protection.

Accordingly, in a further aspect the present invention provides a methodfor the treatment of a tetracycline compound responsive state in asubject, preferably a human, which comprises administering to thesubject an effective amount of a compound of Formula (I) orpharmaceutically acceptable derivative or solvate thereof.

In the alternative, there is provided a compound of Formula (I) or apharmaceutically acceptable derivative or solvate thereof, for use inmedical therapy, particularly, for use in the manufacture of amedicament for the treatment of a tetracycline compound responsivestate.

The term “tetracycline compound responsive state” includes a state whichcan be treated, prevented, or otherwise ameliorated by theadministration of a compound of Formula (I) or pharmaceuticallyacceptable derivative or solvate thereof. Tetracycline compoundresponsive states include bacterial infections (including those whichare resistant to other tetracycline compounds), cancer, diabetes, andother states for which tetracycline compounds have been found to beactive (see, for example, U.S. Pat. Nos. 5,789,395; 5,834,450; and5,532,227). Compounds of the invention can be used to prevent or controlimportant human and veterinary diseases such as respiratory tractinfections, systemic infections and some local infections. Moreparticularly, compounds of the invention can be used to prevent orcontrol diarrhea, urinary tract infections, infections of skin and skinstructure, ear, nose and throat infections, wound infection, mastitisand the like. In addition, methods for treating neoplasms usingtetracycline compounds of the invention are also included (van derBozert et al., Cancer Res., 48:6686-6690 (1988)). In one embodiment, thetetracycline compound is used to treat a bacterial infection. In afurther embodiment, the tetracycline compound is used to treat abacterial infection that is resistant to other tetracycline antibioticcompounds.

For the avoidance of doubt, the term ‘treatment’ as used herein includesprophylactic therapy.

Bacterial infections may be caused by a wide variety of gram positiveand gram negative bacteria. The compounds of Formula (I) are useful asantibiotics against organisms which are resistant to other tetracyclinecompounds. The antibiotic activity of the compounds of Formula (I) maybe determined using the method discussed in the Biological Examplebelow, or by using the in vitro standard broth dilution method describedin Waitz, J. A., National Committee for Clinical Laboratory Standards,Approved Standard M7-T2, vol. 10, no. 8, pp. 13-20, 2^(nd) edition,Villanova, Pa. (1990).

The compounds of the invention may also be used to treat infectionstraditionally treated with tetracycline compounds such as, for example,rickettsiae; a number of gram-positive and gram-negative bacteria; andthe agents responsible for lymphogranuloma venereum, inclusionconjunctivitis and psittacosis. The compounds of Formula (I) may be usedto treat infections of pneumococci, Salmonella, E. coli, S. aureus or E.faecalis.

The term “effective amount of the compound of Formula (I)” is thatamount necessary or sufficient to treat or prevent a tetracyclinecompound responsive state. The effective amount can vary depending onsuch factors as the size and weight of the subject, the type of illness,or the particular tetracycline compound. One of ordinary skill in theart would be able to study the aforementioned factors and make thedetermination regarding the effective amount of the compound of Formula(I) or a pharmaceutically acceptable derivative or solvate thereofwithout undue experimentation.

The invention also pertains to methods of treatment againstmicro-organism infections and associated diseases. The methods includeadministration of an effective amount of one or more compounds ofFormula (I) or a pharmaceutically acceptable derivative or solvatethereof to a subject. Preferably the subject is a mammal e.g., a human.

For human use, a compound of the Formula (I) can be administered as rawdrug substance, but will generally be administered in admixture with apharmaceutically acceptable carrier selected with regard to the intendedroute of administration and standard pharmaceutical practice.

Accordingly, the present invention further provides a pharmaceuticalformulation comprising a compound of Formula (I) or a pharmaceuticallyacceptable derivative or solvate thereof, and one or morepharmaceutically acceptable carriers.

The term pharmaceutically acceptable carrier includes substances capableof being coadministered with the compounds of Formula (I), and whichallow performance of the intended function, e.g., treat or prevent atetracycline compound responsive state. Suitable pharmaceuticallyacceptable carriers include but are not limited to water, saltsolutions, alcohol, vegetable oils, polyethylene glycols, gelatin,lactose, amylose, magnesium stearate, talc, silicic acid, viscousparaffin, perfume oil, fatty acid monoglycerides and diglycerides,petroethral fatty acid esters, hydroxymethyl-cellulose,polyvinylpyrrolidone, etc.

The pharmaceutical preparations can be sterilised and if desired mixedwith auxiliary agents, e.g., lubricants, preservatives, stabilisers,wetting agents, emulsifiers, salts for influencing osmotic pressure,buffers, colourings, flavourings and/or aromatic substances and the likewhich do not deleteriously react with the compounds of the invention.

The compounds of the invention may be administered alone or incombination with pharmaceutically acceptable carriers or diluents. Thecompounds of the invention may be administered via oral, parenteral ortopical routes. The administration may be carried out in single ormultiple doses. The compounds of the invention may be administered in awide variety of different dosage forms, for example they may be combinedwith various pharmaceutically acceptable inert carriers in the form oftablets, capsules, lozenges, troches, hard candies, powders, sprays,creams, salves, suppositories, jellies, gels, pastes, lotions,ointments, aqueous suspensions, injectable solutions, elixirs, syrups,and the like. Such carriers include solid diluents or fillers, sterileaqueous media and various non-toxic organic solvents, etc. Moreover,oral pharmaceutical compositions may be sweetened and/or flavoured. Ingeneral, the compounds of the invention are present in such dosage formsat concentration levels ranging from about 5.0% to about 70% by weight.

For oral administration, tablets may contain various excipients such asmicrocrystalline cellulose, sodium citrate, calcium carbonate, dicalciumphosphate and glycine may be employed along with various disintegrantssuch as starch (and preferably corn, potato or tapioca starch), alginicacid and certain complex silicates, together with granulation binderslike polyvinylpyrrolidone, sucrose, gelatin and acacia. Additionally,lubricating agents such as magnesium stearate, sodium lauryl sulphateand talc may be employed. Solid compositions of a similar type may alsobe employed as fillers in gelatin capsules; preferred materials in thisconnection also include lactose or milk sugar as well as high molecularweight polyethylene glycols. When aqueous suspensions and/or elixirs aredesired for oral administration, the active ingredient may be combinedwith various sweetening or flavouring agents, colouring matter or dyes,and, if so desired, emulsifying and/or suspending agents, together withdiluents such as water, ethanol, propylene glycol, glycerin and variouscombinations thereof.

For parenteral administration (including intraperitoneal, subcutaneous,intravenous, intradermal or intramuscular injection), solutions ofcompounds of the invention in either sesame or peanut oil or in aqueouspropylene glycol may be employed. The aqueous solutions may be buffered(preferably pH greater than 8) if necessary and the liquid diluent firstrendered isotonic. These aqueous solutions are suitable for intravenousinjection purposes. The oily solutions are suitable for intraarticular,intramuscular and subcutaneous injection purposes. The preparation ofall these solutions under sterile conditions is readily accomplished bystandard pharmaceutical techniques well known to those skilled in theart. For parenteral administration, examples of suitable preparationsinclude solutions, preferably oily or aqueous solutions as well assuspensions, emulsions, or implants, including suppositories. Compoundsof the invention may be formulated in sterile form in multiple or singledose formats. For example the compounds of the invention may bedispersed in a fluid carrier such as sterile saline or 5% salinedextrose solutions commonly used with injectables.

The compounds of the invention may be administered topically for examplewhen treating inflammatory conditions of the skin. Examples of methodsof topical administration include transdermal, buccal or sublingualapplication. For topical applications, therapeutic compounds can besuitably admixed in a pharmacologically inert topical carrier such as agel, an ointment, a lotion or a cream. Such topical carriers includewater, glycerol, alcohol, propylene glycol, fatty alcohols,triglycerides, fatty acid esters, or mineral oils. Other possibletopical carriers are liquid petrolatum, isopropylpalmitate, polyethyleneglycol, ethanol 95%, polyoxyethylene monolauriate 5% in water, sodiumlauryl sulphate 5% in water, and the like. In addition, materials suchas anti-oxidants, humectants, viscosity stabilisers and the like alsomay be added if desired.

For enteral application, particularly suitable are tablets, dragees orcapsules having talc and/or carbohydrate carrier binder or the like, thecarrier preferably being lactose and/or corn starch and/or potatostarch. A syrup, elixir or the like can be used wherein a sweetenedvehicle is employed. Sustained release compositions can be formulatedincluding those wherein the active component is protected withdifferentially degradable coatings, e.g., by microencapsulation,multiple coatings, etc.

In addition to treatment of human subjects, the therapeutic methods ofthe invention also will have significant veterinary applications, e.g.for treatment of livestock such as cattle, sheep, goats, cows, swine andthe like; poultry such as chickens, ducks, geese, turkeys and the like;horses; and pets such as dogs and cats.

It will be appreciated that the actual amount of the compound of theinvention used in a given therapy will vary according to the specificcompound being utilised, the particular compositions formulated, themode of application, the particular site of administration, etc. Optimaladministration rates for a given protocol of administration can bereadily ascertained by those skilled in the art without undue burden.

In general, compounds of the invention for treatment can be administeredto a subject in dosages used in prior tetracycline therapies. See, forexample, the Physicians' Desk Reference. For example, a suitableeffective dose of one or more compounds of the invention will be in therange of from 0.01 to 100 milligrams per kilogram of body weight ofrecipient per day, preferably in the range of from 0.1 to 50 milligramsper kilogram body weight of recipient per day, more preferably in therange of 1 to 20 milligrams per kilogram body weight of recipient perday. The desired dose is suitably administered once daily, or severalsub-doses, e.g. 2 to 5 sub-doses, are administered at appropriateintervals through the day, or other appropriate schedule.

It will also be understood that normal, conventionally known precautionswill be taken regarding the administration of tetracyclines generally toensure their efficacy under normal use circumstances. Especially whenemployed for therapeutic treatment of humans and animals in vivo, thepractitioner should take all sensible precautions to avoidconventionally known contradictions and toxic effects. Thus, theconventionally recognised adverse reactions of gastrointestinal distressand inflammations, the renal toxicity, hypersensitivity reactions,changes in blood, and impairment of absorption through aluminium,calcium, and magnesium ions should be duly considered in theconventional manner.

The compounds and pharmaceutical compositions of the invention may beadministered alone or in combination with other known compounds andcompositions for treating tetracycline compound responsive states in amammal e.g. a human. The term in combination with a known compound orcomposition is intended to include simultaneous, concomitant andsequential administration.

Accordingly, the present invention provides a combination comprising acompound of Formula (I) or a pharmaceutically acceptable derivative orsolvate thereof, and a further active ingredient suitable for treatingtetracycline compound responsive states in a mammal e.g. a human.

Compounds of Formula (I) and pharmaceutically acceptable derivatives andsolvates thereof may be prepared by general methods outlined hereinafterwhere the groups R, R¹, R² and R³ have the meaning defined for compoundsof Formula (I) unless otherwise stated.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a pyrrolering optionally substituted by one or more group R or a pharmaceuticallyacceptable derivative or solvate thereof which process comprisesreacting a compound of Formula (II) with a compound of Formula (III)wherein Ra and Rb are hydrogen or C₁₋₆alkyl under dehydrating conditionsfor example in the presence of sulphuric acid in methanol.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a pyrrolering optionally substituted by one or more group CHNORa or apharmaceutically acceptable derivative or solvate thereof which processcomprises reacting a compound of Formula (IV) with NH₂ORa in water.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a pyrrolering optionally substituted by one or more group cyano or apharmaceutically acceptable derivative or solvate thereof which processcomprises reacting a compound of Formula (V) with acetic anhydride andformic acid.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a pyrrolering optionally substituted by one or more group CH₂NRaRb or apharmaceutically acceptable derivative or solvate thereof which processcomprises reacting a compound of Formula (IV) with NHRaRb underdehydrating conditions for example in the presence of acetic acid,methanol and water and then subjecting the product to a reducing agentsuch as sodium cyanoborohydride.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a tetrazolering or a pharmaceutically acceptable derivative or solvate thereofwhich process comprises reacting a compound of Formula (II) withisobutyl nitrite in methanolic hydrochloric acid followed by treatmentwith a mixture containing sodium azide and triethyl orthoformate inacetic acid.

According to a further aspect of the invention, there is provided aprocess for preparing a compound of Formula (I) wherein A is a1,2,3-triazole ring optionally substituted by one or more group CO₂Ra ora pharmaceutically acceptable derivative or solvate thereof whichprocess comprises reacting a compound of Formula (II) with isobutylnitrite in methanolic hydrochloric acid followed by treatment withsodium azide to afford the corresponding 7-azido intermediate, and thensubjecting the 7-azido intermediate to a reaction with alkylpropiolatein dioxane under reflux conditions.

The invention will now be illustrated by way of the following Exampleswhich should not be construed as constituting a limitation thereto.

EXAMPLE 1 [4(R,S)-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-(1H-Tetrazol-1-yl)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

A mixture of 7-amino-sancycline (50 mg), triethyl orthoformate (100 μl)and sodium azide (20 mg) in glacial acetic acid (5 ml) was heated to 80°C. for 2 h, then cooled to ambient temperature. This mixture was addeddropwise at room temperature onto a solution of Isobutyl nitrite (60 μl)in 10 ml of methanolic hydrogen chloride (prepared by dissolving 0.83 mlof concentrated HCl in 100 ml of methanol). The solution was stirred atroom temperature overnight, then poured onto diethyl ether and theresulting solid filtered-off and washed with diethyl ether. Thismaterial was purified by MPLC chromatography on silica gel C18. 10 mg ofthe pure material was isolated as a mixture 1:1 of two epimers at4′-position.

MS (e.s.+): m/z 483 (M⁺+H)

¹H-NMR (CD₃OD): 9.42, 9.40 (2s, 1H, H5′-Tetrazole); 7.60, 7.59 (2dd, 1H,H8, J₁=J₂=9 Hz); 7.06, 7.05 (2dd, 1H, H9, J₁=J₂=9 Hz); 4.81 (d, 0.5H,H4, J=3 Hz); 4.02 (bs, 0.5H, H4)

EXAMPLE 2[4-S-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-[(4-ethoxycarbonyl)-1H-triazol-1-yl]-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide[4-S-(4aα,5aα,12aα)]-4-(Dimethylamino)-7-[(5-ethoxycarbonyl)-1H-triazol-1-yl]-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

1) Preparation of 7-azido-Sancycline:

To a suspension of 7-amino-Sancycline (50 mg) in 2 ml of methanolichydrogen chloride (prepared by dissolving 0.83 ml of cc HCl into 100 mlof methanol) was added at 0° C. (ice-water bath) isobutyl nitrite (60μl). The mixture was stirred at 0° C. for 1 h, then sodium azide (6.5mg) was added at once. The mixture was stirred at r.t. for 2 h, thenpoured onto cold diethyl ether. The solid was filtered-off and washedwith diethyl ether. 50 mg of 7-azido-Sancycline (m/z: 456, M⁺+H) wasobtained as a powder, which was used without further purification.

2) Cycloaddition:

The above powder (50 mg) was suspended in dioxane (5 ml) and ethylpropiolate (100 μl) was added with stirring. The suspension was stirredfor a few minutes at room temperature, then heated to reflux until HPLCanalysis showed no remaining 7-azido-derivative (3 h aprox). The mixturewas cooled down to room temperature and poured onto cold diethyl ether.The precipitate obtained was separated by filtration and washed withdiethyl ether. The crude thus obtained was purified by preparative HPLC,affording a sample of 10 mg of a mixture of regioisomers.

MS (e.s.+): m/z 554 (M⁺+H)

[4S-(4aα,5aαα12aα)]-7-(Amino)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide(7 amino sancycline) is synthesised as described in U.S. Pat. No.3,403,179

EXAMPLE 3[4S-(4aα,5aαα,12aα)]-4-(Dimethylamino)-7-(1H-pyrrol-1-yl-3-carboxaldehyde)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

A mixture of 2,5-dimethoxy-3-tetrahydrofurancarboxaldehyde (0.35 ml) and2.5M sulfuric acid (1.2 ml) was added dropwise to an open vesselcontaining a methanolic solution (10 ml) of the aniline (0.6 g) andstirred at room temperature for 2 h. The reaction mixture wasprecipitated in cold ether and filtrate to give a brown residue whichwas dissolved in water, freeze and lyophilised. The residue was purifiedusing C18-F40 Biotage column chromatography. Pure compound (0.425 g) wasobtained after lyophilisation of the appropriate fractions.

H-RMN (CD₃OD): 9.71 (s, 1H, CHO), 7.61 (bt, 1H, H-2pyrrole), 7.48 (d,1H, H-8, J=8.7 Hz), 6.95 (d, 1H, H-9), 6.91 (m, 1H, H-5pyrrole), 6.71(dd, 1H, H-4-pyrrole, J=1.6 and 3.0 Hz), 4.01 (d, 1H, H-4, J=1.1 Hz).

MS (e.s.+): m/z 508.15 (M⁺+H)

EXAMPLE 4[4S-(4aα,5aαα,12aα)]-4-(Dimethylamino)-7-(3-((hydroxymino)-methyl)-1H-pyrrol-1-yl)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

A water solution (12 ml) of carboxaldehyde (Example 3) (0.17 g) wasstirred for 2 h in the presence of a two fold excess of hydroxylaminehydrochloride. The reaction mixture was freeze and lyophilised, and thenfiltrate on RP2 silica gel to give a 1:3 mixture of syn:anti isomers ofthe oxime in quantitative yield.

H-RMN (CD₃OD): syn isomer: 8.0 (s, 1H, CH═N), 7.45 (d, 1H, H-8, J=8.7Hz), 7.02 (bt, 1H, H-2pyrrole), 6.93 (d, 1H, H-9), 6.76 (m, 1H,H-5pyrrole), 6.52 (dd, 1H, H-4pyrrole, J=2.8 and 1.7 Hz), 4.02 (bs, 1H,H-4).

H-RMN (CD₃OD): anti isomer: 7.52 (bt, 1H, H-2pyrrole), 7.47 (d, 1H, H-8,J=8.7 Hz), 7.27 (s, 1H, CH═N), 6.93 (d, 1H, H-9), 6.77 (m, 1H,H-5pyrrole), 6.61 (dd, 1H, H-4pyrrole, J=1.7 and 2.8 Hz), 4.02 (bd, 1H,H-4, J=1.5 Hz).

MS (e.s.+): m/z 523.2 (M⁺+H)

EXAMPLE 5[4S-(4aα,5aαα12aα)]-7-(3-Cyanopyrrol-1-yl)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

The oxime (Example 4) (0.06 g) in a 1:1 mixture of acetic anhydride andformic acid (4 ml) was stirred at 90° C. for 2 h. The reaction mixtureat room temperature was precipitated in cold ether and filtrate to givea brown residue which was dissolved in water, freeze and lyophilised.The residue was purified using a C8 Luna semi-preparative HPLC to givepure nitrile (0.027 g) as a yellow powder after lyophilisation of theappropriate fractions.

H-RMN (CD₃OD): 7.49 (bt, 1H, H-2pyrrole), 7.47 (d, 1H, H-8, J=8.7 Hz),6.95 (d, 1H, H-9), 6.90 (dd, 1H, H-5pyrrole, J=2.1 and 2.8 Hz), 6.58(dd, 1H, H-4pyrrole, J=1.6 and 2.8 Hz), 4.01 (bs, 1H, H-4).

MS (e.s.+): m/z 505.3 (M⁺+H)

EXAMPLE 6[4S-(4aα,5aα12aα)]-4-(Dimethylamino)-7-(3-((methyloxymino)methyl)-1H-pyrrol-1-yl)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide

A water solution (10 ml) of carboxaldehyde (Example 3) (0.085 g) wasstirred for 2 h in the presence of a two fold excess of methoxylaminehydrochloride. The reaction mixture was freeze and lyophilised, and thenpurified using a C8 Luna semi-preparative HPLC. A 1:2 mixture of thesyn:anti isomers of the O-methyloxime was isolated (0.057 g) as a yellowpowder after lyophilisation of the appropriate fractions.

H-RMN (CD₃OD): syn isomer: 8.01 (s, 1H, CH═N), 7.45 (d, 1H, H-8, J=8.7Hz), 7.04 (bt, 1H, H-2pyrrole), 6.93 (d, 1H, H-9), 6.77 (m, 1H,H-5pyrrole), 6.52 (dd, 1H, H-4pyrrole, J=2.9 and 1.6 Hz), 4.02 (bs, 1H,H-4), 3.83 (s, 3H, OCH₃).

H-RMN (CD₃OD): anti isomer: 7.46 (d, 1H, H-8, J=8.7 Hz), 7.42 (bt, 1H,H-2pyrrole), 7.25 (s, 1H, CH═N), 6.94 (d, 1H, H-9), 6.76 (m, 1H,H-5pyrrole), 6.58 (dd, 1H, H-4pyrrole, J=1.6 and 2.9 Hz), 4.02 (bd, 1H,H-4, J=1.5 Hz), 3.92 (s, 3H, OCH₃).

MS (e.s.+): m/z 537.3 (M⁺+H)

Biological Examples

MIC EXAMPLE EXAMPLE EXAMPLE EXAMPLE (μg/ml) 3 4 5 6 S. aureus 0.015 0.120.015 0.12 ATCC 29213 S. aureus 0.25 0.5 0.5 0.5 GFX01596 Tet R S.pneumoniae 157 0.015 0.03 0.015 0.06 S. pneumoniae 2 2 2 4 GFX01778 TetR H. influenzae 1 2 0.5 2 ATCC 49247 M. catarrhalis 0.008 0.03 0.0010.004 ATCC 23246 E. coli 0.5 1 0.5 2 ML 308-225

Growth-inhibitory activity was determined on liquid medium by theantibiotic dilution technique using 96-well microtiter system platescontaining two-fold dilutions of antibiotic-agent in 0.2 ml. ofMueller-Hinton broth. Plates were inoculated with each test organism toyield a final inoculum of 5×10⁵ CFU/ml and were incubated aerobically at37° C. for 18 h. The MIC was defined as the lowest concentration ofantibacterial agent that inhibited development of visible growth in themicrodilution wells.

Equivalents

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thespecific procedures described herein. Such equivalents are considered tobe within the scope of the present invention and are covered by thefollowing claims. The contents of all references, patents, and patentapplications cited throughout this application are hereby incorporatedby reference. The appropriate components, processes, and methods ofthose patents, applications and other documents may be selected for thepresent invention and embodiments thereof.

1. A compound of Formula (I):

wherein: A represents a pyrazole ring optionally substituted by one ormore R groups, wherein R is selected from: halogen, —NRaRb, C₁₋₆alkyl,C₂₋₆alkenyl, C₃₋₆alkynyl, aryl, heteroaryl, hydroxy, —OC₁₋₆alkyl,formyl, cyano, trifluoromethyl, —CHNORa, —CO₂Ra, —CONRaRb, —NRaC(O)Ra,—NRaC(O)ORa, —OC(O)NRaRb, —OC(O)Ra, —OC(O)ORa, and a C₁₋₆alkyl groupsubstituted by one or more groups selected from: hydroxy, —NRaRb,—OC₁₋₆alkyl, —SRa, —CHNORa, —CO₂Ra, —CONRaRb, —NRaC(O)Ra, —NRaC(O)ORa,—OC(O)NRaRb, —OC(O)Ra, and —OC(O)ORa, wherein: Ra and Rb independentlyrepresent hydrogen or C₁₋₆ alkyl; R¹ represents hydrogen, C₁₋₆ alkyl ortogether R¹ and R³ represent a CH₂ moiety; R² represents hydrogen,—OC₁₋₆ alkyl, —OC(O)C₁₋₆alkyl or hydroxy; R³ represents hydrogen,hydroxy or together R³ and R¹ represent a CH₂ moiety, or apharmaceutically acceptable salt thereof.
 2. The compound of claim 1,wherein R¹, R² and R³ are each hydrogen.
 3. The compound of claim 1,wherein R¹, R² and R³ are each hydrogen and further wherein A isunsubstituted.
 4. The compound of claim 1, wherein A is substituted withethoxycarbonyl, carboxaldehyde, cyano, dimethylaminomethyl, oxime ormethyloxime.
 5. A method of ameliorating a bacterial infection in asubject in need thereof, which comprises administering to the subject aneffective amount of a compound of claim 1, wherein the infection iscaused by S. pneumoniae, S. aureus, H. influenzae, M catarrhalis, E.coli, pneumococci, salmonella, or E. faecalis.
 6. The method of claim 5,wherein said subject is a human.
 7. A pharmaceutical formulationcomprising a compound of claim 1 and one or more pharmaceuticallyacceptable carriers.
 8. The compound of claim 1, wherein R¹ isC₁₋₆alkyl, R² is hydroxy and R³ is hydrogen.
 9. The compound of claim 1,wherein R¹ is C₁₋₆alkyl, R² is hydroxy, R³ is hydrogen, and furtherwherein A is unsubstituted.
 10. The compound of claim 1, wherein R¹ isC₁₋₆alkyl, R² is hydrogen and R³ is hydroxy.
 11. The compound of claim1, wherein R¹ is C₁₋₆alkyl, R² is hydrogen, R³ is hydroxy, and furtherwherein A is unsubstituted.
 12. The compound of claim 1, wherein R isselected from: halogen and —NRaRb.
 13. The compound of claim 1, whereinR is selected from: C₂₋₆alkenyl and C₃₋₆alkynyl.
 14. The compound ofclaim 1, wherein R is selected from: aryl and heteroaryl.
 15. Thecompound of claim 1, wherein R is selected from: hydroxy, —OC₁₋₆alkyl,and formyl.
 16. The compound of claim 1, wherein R is selected from:cyano and trifluoromethyl.
 17. The compound of claim 1, wherein R isselected from: —CHNORa, —CO₂Ra, —CONRaRb, —NRaC(O)Ra and —NRaC(O)ORa.18. The compound of claim 1, wherein R is selected from: —OC(O)NRaRb,—OC(O)Ra and —OC(O)ORa.
 19. The compound of claim 1, wherein R isC₁₋₆alkyl.
 20. The compound of claim 1, wherein R is a C₁₋₆alkyl groupsubstituted by one or more groups selected from: hydroxy, —NRaRb,—OC₁₋₆alkyl, —SRa, —CHNORa, —CO₂Ra, —CONRaRb, —NRaC(O)Ra, —NRaC(O)ORa,—OC(O)NRaRb, —OC(O)Ra, and —OC(O)ORa.